油气地质与采收率2024，Vol.31Issue(2)：119-127,9.DOI:10.13673/j.pgre.202311032
灰岩储层多级交替注入酸压酸蚀规律研究
Acid-etching fracturing law of multi-stage alternating injection in limestone reservoirs
摘要
Abstract
The majority of limestone reservoirs in China are characterized by deep burial,low porosity,and low permeability and are influenced by factors such as elevated temperatures,high closure pressures,and strong heterogeneity.Conventional hydrochlo-ric acid fracturing techniques often fail to achieve non-uniform etching on such reservoirs,resulting in poor transformation effects and hindering the efficient development of such reservoirs.The acid fracturing technology of multi-stage alternating injection was used to facilitate non-uniform etching of fracture wall surfaces by iteratively forming viscous fingering in the prepad.However,the law governing the acid-etching fracturing of multi-stage alternating injection remains unclear,and the acid injection stage boundar-ies are not determined.At present,acid fracturing design typically relies on empirical approaches.To address these gaps,this study built an acid fracturing model of multi-stage alternating injection for limestone reservoirs by considering the influence of viscosity variation and alternating stages based on a two-scale continuous acidification model.Based on the acid fracturing model of multi-stage alternating injection,the influence of acid viscosity,acid injection rate,and acid injection stages on the acid fracture effects was analyzed by combining the acid rock reaction kinetics,acid-etched fracture experimental data,and numerical simulation re-sults.The acid-etching law of multi-stage alternating injection in limestone reservoirs and the acid injection stage boundaries were determined,and the breakthrough volume of acid fluid was introduced to provide the basis for site optimization.The findings sug-gest that to enhance the non-uniform etching of fracture wall surfaces and obtain high conductivity of acid-etching fractures,an al-ternating injection process involving hydrochloric acid and thickened acid should be adopted for pure limestone reservoirs at a for-mation temperature of 90℃.0.4%HPAM-thickened acid should be added when the acid injection rate is 5 m3/min,with an optimal acid injection stage of no more than three.At this time,the breakthrough volume of acid fluid is the smallest,which is suitable for on-site construction.关键词
多级酸压/注酸级数/酸蚀裂缝/稠化酸/灰岩Key words
multi-stage acid fracturing/acid injection stage/acid-etched fracture/thickened acid/limestone分类
能源科技引用本文复制引用
路依鑫,齐宁,周顺明,王转转,李雪松,苏徐航,王亮亮..灰岩储层多级交替注入酸压酸蚀规律研究[J].油气地质与采收率,2024,31(2):119-127,9.基金项目
"十三五"国家科技重大专项"碳酸盐岩复合深度改造优化设计方法及配套技术研究"(2017ZX05030005-002-003),山东省自然科学基金项目"基于蚓孔竞争机制的自转向酸酸蚀蚓孔描述及动态酸化模拟研究"(ZR201702180073). （2017ZX05030005-002-003）
